Automatically-gripping chuck



O. SEFFERT lAUTOMATISALLY GRIPPING CHUCK Ag. 31 l92.

Patented l ug. 31, 1926.

L UNITED STATES lo'r'ro snrnrnnr, or miriam-AUSTRIA.

AUroMA'ricALLY-enrrrme cnucx.

Applicationnled Hay 22, 1922, sueriatlo.

j that the gripping and releasing parts are the ard and couplingmembers.'

mounted in .the main or cam member so that the height of the chuck onlyexceeds the length of the jaws by very little, the diameter of the chuckremaining approximately normal. The power-transmitting or locking camfaces are in the main or cam member which may be secured direct totheworking spindle of themachine. In this way the upper wall is dispensedwith and is replaced by `the spindle which takes up the axial thrust ofthe gripping jaws.

-A construction according tothe present' invention is illustrated in theaccompanyindrawings, in which.

igure 1 is a longitudinal section along the line A-B of Figure'2, and 'jFigure'2 is a section along the line C, D, E, F of' Figurel.

' Fig. 3 illustrates in horizontal section the `bayonet joint forconnecting the cam and cave members.

Fig.` 4 shows in side elevation, partly in section, the means forrotatably coupling ,cam member l carries the gripping members or jaws 2which in the present case are cylindrical rollers 2 guided :in a cageringI 3 the latter having extensions projectmg into a recess in the cammemberv nd an annular flange extending beyond and engaging the outerface of the cam member. In the illustrated embodiment -the cage ring 3is secured to the member 1 in .the manner of a bayonet-joint such as byinwardly projecting portions 4 secured to the flange of the cage ring 3.In a certain position ofI the cage ring 3 and the member 1, the saidpinsY pass through recesses in the projecting bottom of the member 1 and are`caused to rest` on the same by a relativerotation of the cage ring`3with respect to the member 1.

The latter surrounded by' the clamping or locking member 5 connected tothe camf memberl by a helical spring 6 arranged in a -circlevand locatedartially in 'a recess of the cam member an portion of the lockingmember. As

Pertially in a recessed 562,843, ana in creat Britain pril s, 1922.,

l man1-.. ATENT oFFlcE.

trated in Figure 2, olie end of the spring isl j fastened to a pin9 ofthe locking member 5, and the other to a pin 8 of the cam member 1 -sothat'the said spring constantly tends tokeep the latter and the lockingmember 5in adeinite relative position. Anotherpin 7 secured tothe outeredge of the flange of the cage ring engages the. spring 6.- The latteryis compressed through the pins -8 and 9 when the locking member 5 isrotated relatively to the cam member 1, the

cage ring 3 being moved through the pin 7L The gripping jaws or rollersare thuscaused to. move along the cam faces and. are also `radiallydisplaced untily they bear onvthe workpiece .introduced into the openingof the'chuck. On further rotating the membery A 5, the portion of thespring 6 comprised between the' pins 7 and9 is further compressed sothat the grippin jaws are always kept under pressure.

0' When force isyexe'rted on the workpiece the jaws roll further on `andj' I are therefore wedged tighter betweenv the workpiece and the cam.faces so that the gripping pressure is automatically increased. l Y YThe locking member has -now to be locked in this position of the parts;in theexam le f illustrated a ratchet device'is provided'. or 8l thatpurpose. Asuitable portion of the outer face of the cam member 1 hasratchet teeth lOcooperating with a spring pawl 11 riveted to the lockingmember 5.v This arrangement allows- (as known) of the relative rotationof the two partsin one direction only, the said parts being locked whenrotatedrin the opposite direction. kThe cam o member hasa recessedportion 12 above the ratchet teeth so that the pawl 11 'lies inthe saidrecessed portion when the lockingl memberis shifted axially, thusreleasing t e connection between. the locking'and cam members. andcausing the spring 6 andthe arts operated thereby to resume theirnormaposition. The cage ring beingl now in its' in itial position, theopening of the chuck 1s roughtto zero; A further advantage of t isarrangement is that the awll-l in the groove 12 prevents the locking'member 5 from slipping olf the cam member and when the said member isshifted again the pawlv automatically locks the'parts.

As already` stated, hechuck may be tlghtened and released whilethe'apparatus is operative, the locking member particlpatm inthe'rotation of the cam member,

guard'orlouter protecting caslng 13 covers lmeans of projections, wedgesor the like.

In' the Yconstruction illustrated the lower portion of 'the' lockingmember is in the shape of a cone against which the outer casingl bears.This conical-portion acts Valso as a friction clutch exercising actionupon the locking` member when the chuck is tightcned.` The lockingmember has an annular groove 14fcut in the vicinity of its upper edgetoreceive one or more pins 15- traversing the outer casing or guard 1 3so-that any axial movement of the said casing is followed by the lockingmember. y

The pins 15 are prevented lfrom .falling out by cut-ting a `dat 'on theend of the pm engaging the groove 14, thelatter being in cross-sectionadapted to the 'shape of the pin, so that the same cannot be turned or vaxially moved.

The groove is widened at a suitable place to correspond to the diameterof the pin, in order to ofer no obstacle or resistance to the insertion'of the pin.

According to the invention, the gripping jaws 2 have chisel-shapedprojections to prevent the workpiece from slipping axially. VThe saidjaws bein cylindrical in the construction illustrate these projectionsare annular rings or collars of suitable cross-section which of courseproject but to a small extent on the faces of the jaws.

1. A cam operated chuck comprising a cam member, an operating sleevemember, and a jaw carrying cage, said sleeve and cage being rotatablerelatively to said cam member in actuating?, the jaws; a coil springrotation of said sleeve further compressing the spring with relationtosaid cage to keep the cage and.v jaws under steady pressure, and meansto lock the chuck in the operative position.

2. A ,cam operated chuck, such as covered by claim 1, in which a. pinengaging the spring intermediate its ends and connected to the cagedetermines the position of the part of the spring which is subjected' tothe further compression.

3. A cam operated chuck, 'such as covered by claim 1, in which saidoperating sleeve is adjustable axially in one dlrection toe connectv itwith the cam member by a locking device to lock the chuck in theoperative position and in which said sleeve isadjustable axially in theother direction to disengage it from the cam .member to open` 'thechuck.

4. A cam operated chuck, such as covered by claim 1, in whichi thelocking means is operated by the axial adjustmentl of the sleeverelativelyl to said cam member and i comprises` a spring pawl secured tothe sleeve and cooperating upon axial movement of said sleeve in onedirection, with ratchet teeth on the cam member and, upon movement ofsaid sleeve' in the other directhe upper wall ofthe groove cooperatingwith said spring to form a stop preventingthe sleeve from slipping offthe cam member.

In testimony whereof I aix my si ature. OTTO SEIFF RT.

